Purification and deodorization process



Feb. 6, 1945. A. P. LEE ErAL PURIFICATION AND DEODORIZATION PROCESSFiled July 11, 1939 5 SheetsSheet 1 tfmm lli

Feb. 6, 1945. A. P. LEE ETAL PURIFICATION AND DEODORIZATION PROCESSFiled July 11, 1939 5 Sheets-Sheet 2 Rs dead. WWA; MINVENTO By ma; hay,v /df ,/y. ma., ATTORNEY.

Feb. 6, 1945. A. P. LEE Erm. 2,368,669

PURIFICATION AND DEODORIZATION PROCESS Filed July 11, 1939 5Sheets-Sheet 3 Feb. 6, 1945. A. P. LEE ETAL PURIFICATION ANDDEODORIZATION PROCESS Filed July 1l, 1959 5 Sheets-Sheet 4 58 ab Zw@INVENTORS @Aff/ff.

ATTORNEY;

IFeb. 6, A P, LEE ETAL PURIFICA'IION AND DEODORIZATION PROCESS FiledJuly 11, 1959 v 5 sheets-sheet 5 zewwn w SC NSS Patented Feb'. 6., 1945UNITED STATES VPATENT OFFICE PURIFICATION AND DEODORIZATION PROCESS AlanPorter Lee, Madison, and Walter Gray King, Jr., Montclair, N. J.

Application July 11, 1939, Serial No. 283,720

12 Claims.

This invention relates to improvements in processes, methods andapparatus for distillatory purification or deodorization of glycerideoils. By glyceri-de oils we mean to designate fatty oils or fatsy ofanimal, vegetable or synthetic origin. Throughout our application belowWe use the terms glycerida glycerides glyceride oils and liquidinterchangeably, such terms being understood to refer herein to thoseglyceryl esters or mixtures of esters of fat acids which are commonlycalled fats, fatty oils, "fixed oils or glycerides, regardless of theirorigin. By the term fat acid"as used herein we mean any organic acidnaturally occurring in fats or oils, either in a glyceryl ester or asuncombined aci-d, or any synthetic homologue of any such acid; all suchacids, natural or synthetic, often being referred to as fatty acids.

Methods of purifying and deodorizing glyceride oils by distilling awayvolatile impurities have been practiced extensively for manyy years andhave developed from simple early empiric forms to more modern methods inwhich the principles of physical chemistry and chemical engineering areapplied to the processes involved.

The basic operation is the application of heat for volatilization of theimpurities while so controlling such heat application that thetemperature of vaporization of the oil being deodorized or purified willnot Ibe reached and that degradation. or decomposition of said oil fromthe effect of heatingvwill be minimized. An important application ofsuch distillatory deodorizing and purifying processes is to be found intreatment of the glycerides, (oils and fats), natural, synthetic, orhydrogenated, for food product manufacture.

A11 natural fats and oils, animal or vegetable, as found in naturecontain small percentages of substances other than the glycerides of thefat acids and it is from these small percentages of non-glyceridicsubstances that the natural odors and flavors of the fats and oils arederived. Such natural odors and flavors are not unpleasant in glyfcridesfreshly produced from choice raw materials. In the ch/annels ofcommerce, however, it is inevitable that considerable time will elapsebetween the formation of fats and oils in their animal or vegetablesources and -their arrival on consumers tables in the form of food orfood ingredients. During such lapse of time certain deffenerativechanges often occur which alter the flavors of the natural fattysubstances. generally rendering them less palatable. Such changesinclude greater or less decomposition of the flavorgeneratingsubstances; slight decomposition or oxidation of the coloring matterswhich are also present in very minute percentages; partial hydrolysis ofthe glycerides themselves, with formation of glycerine and free fatacids; decomposition of the glycerine so formed into alcohols of lowerhydroxylation and into acrolein.I

Such changes cause the pleasant flavors and odors of natural fats to rbereplaced by others less pleasant. In many instances, furthermore, it isdesirable to remove even the pleasant flavors of fresh natural fats oroils, as the collective preference of the consuming public demands moreand more bland, neutral-flavored fats and oils, which are subject toflavoring to taste by means of kitchen seasonings.

In modern refining and processing of fats and oils, contact of thesematerials with various chemical substances such as the alkalies used toremove the bulk of the free fat acids, the bleaching materials used forcolor improvement, or the catalytic substances employed to influencehydrogenation, causes injury to the natural flavor and not infrequentlythe addition of undesirable foreign flavors and odors.

Fats and oils are seen thus for several reasons to require deodorizationfor improvement of flavor as well as of odor, and to procure thisdeodorization distillatory methods are in universal use.

The basis of all methods of distillatory deodorization of oils is theapplication of heat for vaporization of the small percentages ofsubstances which impart flavors and odors to the oil being deodorized,while carefully limiting the amount and range of heat input in order to`minimize thermal or oxidative decomposition of the oil under treatmentand to avoid vaporization of the main body of said oil.

As applied to fats and oils, the distillatory deodorization Process hasdeveloped throughseveral stages, including: first, simple heating forvolatilization of odorous substances; second, addition of steam or othernon-reacting vapor or gas during the heating, to complement the vaporpressureyof the substances to be distilled away, thus lowering thetemperature of'their volatiliization; third, superheating steam so usedto increase its thermal effectiveness; fourth, reducing the totalpressure in the distilling vessel by means of condensers for thedistillate and for the steam, thus further reducing the temperature' ofthe desired distillation and at the same time "reducing the degree ofincidental oxidative decomposition of thel fat or oil being deodorized.

procedure include: reduction in time of treatment; reduction 'in size ofnecessary apparatus for a given output capacity; economy in fuel becauseof lowez` radiation losses of smaller apparatus as well as because offacility of heat exchange between incoming and outgoing materials;economy in the use of distilling steam through application of theprinciple of counterflow to the passage of steam and liquid through thedistilling apparatus.

Most of these objectives can be obtained by the application of wellknown apparatus and methods in continuous operation, as, for example,heating a flowing stream of the oil to be deodorized in a continuoustubular heater, passing said oil to the upper portion of a vacuumbubble-tray tower or similar apparatus, where it encounters in itsdescent over the trays a rising current of superheated steam, by the aidof which the undesired volatiles, (ketones, aldehydes, free fat acidsand the like), are vaporized, passing from the tower top with the steamto suitable condensation apparatus. The treated oil, presumably entirelydeodorized, flows from the bottom of the vacuum tower through suitableheat economizing apparatus, where it transmits heat to the incomingliquid feed, thence to a point of further cooling, iinally to storage oruse.

In the practical, application of the above-cited basic principles to thecontinuous deodorization of fats and oils, there are importantadditional requirements which must be met in order to insure nishedproducts of the highest quality. 'I'hese requirements are applicable to,and are limitationsoi' all distillatory deodorization operations,whether of the batch or continuous type, and it is toward thefulfillment of these re-` quirements in continuous operation that ourpresent invention is directed.

'Ihese requirements and limitations may be set forth briefly here asfollows:

1. Practially all the oils which are subject to distillatorydeodorization are of delicate constitution and are readily subject tothermal decomposition, therefore the heating method selected must be ofsuch character that thermal decomposition is avoided.

2. Oxidative changes also must be avoided insofar as possible, thereforethe distillation must be conducted at the lowest practical absolutepressure, not only for thermal economy, but also for the exclusion ofoxygen or air.

3. Experience has shown that the optimum conditions for most completevaporization of the odorous volatile substances are attained at miximumsafe temperatures and minimum absolute pressures, therefore since acertain amount of pressure drop is inevitable in all practicalcounter-current vacuum distilling apparatus, provision must be made forample contact of the oil being deodorized with the steam or other inertgaseous carrier at the condition of minimum i pressure in conjunctionwith maximum temper- 'ature.

4. Redux condensation into the oil being deodorized, of even smallamounts of the odorous distillate must be prevented by suitable methodsand means. The return of separated entrained liquid is undesirable also,because such entrainment is usually contaminated with odorous substanceswhen separated i'rom the stream of distillate vapors.

5. In al1 counter-current apparatus arranged for contact of* liquids andgases or vapors, there is possibility of considerable short-circuitingflow of untreated liquid through the apparatus into the completelytreated liquid in the lower portion of said apparatus, therefore, sinceeven a small amount of untreated oil will contaminate a large amount ofdeodorized oil and render the deodorization useless, provision must bemade for effective prevention of even slight flow of untreated oil intothe finished deodorized product.

6. The finished deodorized oil must not be exposed to the action ofoxygen or to that of atmospheric air until thoroughly cooled, thereforesuitable cooling apparatus of vacuum or inertgas-charged type must beprovided.

7. In order to obtain maximum 'cieodorization or distillation effect,steam or other inert gas in a condition of purity, that is ofsubstantial freedom from admixture or saturation with the volatileproducts of deodorization or distillation, must be applied to the oilbeing deodorized or purified, under conditions of minimum pressure andelevated temperature.

8. In order that the volatile substances shall be completely vaporizedwith the aid of minimal quantities of distillation steam, the vaporpressures of such substances at the superior liquid surfaces must bemaintained at practical maxima, therefore dilution of theleast-deodorized oil subjacent to such superior liquid surfaces must beavoided insofar as is practicable.

It is an object of our present invention to provide a continuous processfor distillatory deodorization or purification of glycerides which willmeet any and all of the above-listed requirements and limitations.

Another object of our invention is to provide a method of distillatorydeodorization or purification of glycerides in which purified glyceridesof superior quality will vbe readily obtained.

The above-mentioned objects and other objects of our invention Will befully understood from the following description in conjunction with theaccompanying drawings which diagrammatically show preferred embodimentsof our invention.

The drawings herewith represent equipment assemblies suitable for use inapplication of our invention, as well as typical process-flow therein,but these drawings are not to be construed as limitations of ourinvention, except insofar as they may represent new features ofapparatus structure or` assembly hereinbelow claimed.

In order that our invention may be clearly understood, we refer to thedrawings herewith, in which:

Figure l is a diagrammatic elevation, partly in section, of one form ofapparatus suitable for operation of our invention.

Figure 2 is a diagrammatic elevation, partly in section, of a variantform of apparatus for said operation.

Figure 3 is a diagrammatic elevation, partly in section, of an alternateform of the apparatus shown in Figure 1.

Figure 4 is a detail, in cross-section, of a pornon of maure 1, y y

paratus for automatic transfer or liquid `from av of apzone ofrelatively low absolute pressure to a zone vof even lower pressure.'

Figure is a view, partly in section, of the upper portion of adeodorizing or distilling tower, embodying our arrangements forprevention of reflux of separated entrainment or condensed volatiles tothe body of liquid undergoing treatment. i

Figure 6 is a graphic representation of controlled time-cycle operationas practiced in the process of our invention.

Referring to Figure 1, which, as stated above, is an elevation, partlyin section, of one form of our process apparatus, pump 8 is a 'meteringpump through which a glyceride oil .to be Duried or deodorized is fed tothe apparatus in a controlled continuous stream, from any suitablesource, (not shown).

The oil to Ibe treated ows from pump 8 through the pipeline 8a and thespray distributor 9, from which it falls in the form of drops or sprayin the body of the vacuum de-aerating chamber I0, in which said drops orsprayof the oil to be deodorized or purified are brought into intimatecontact with a stream of water-free inert gas, such as nitrogen or'car-bon dioxide gas, which is admitted to the de-aerator IB from thepressure-storage cylinder II through the pressure-reducing andregulating valve I2. One or f.' apoaooef "toi the heating coil 23 in thefurnace 24,' where more bubble-cap trays I3, o-r equivalent devices forpromotion of counter-current contact between liquid and gas, areinstalled in the vacuum de-aerating chamber I0 between the spraydistributor 9 and the point of entrance of the inert gas coming from thecylinder I I.

The vacuum de-aerating chamber I0 is connected by the pipeline I4 to anysuitable highvacuum apparatus, (not shown), or to the upper portion ofthe purifying column I5, which is= maintained at high vacuum. Initspassage as,

drops or spray through the de-aerating ch'aniber, by the combined actionof the vacuum and f the counter-stream of inert gas, the'oil undergoingpurication is freed of dissolved oxygen,

y air or other undesirable non-condensable gases,

all of these being replaced by the inert gas such as nitrogen or carbondioxide gas.

Falling to the lower portion of the de-aerator ID, the glyceridesundergoing treatment form a pool the depth Aof which is regulated by theloop in the pipeline I6 and the vacuum-vent line I1 connecting said loopwith the de-aerating chamber I0. From` the pool so maintained in thelower portion of the de-aerating chamber I0, the deaerated oil is drawnin controlled quantity through the pipeline I6 by the metering pump I8and is discharged through the pipeline I9 and theshell-and-tube heatexchanger 20, in passing through which latter it absorbs considerableheat from the outi'lowing puried oil, which flows counter-currentlythrough the exchanger 28, as-

it is heated by any suitable lmeans. such as-by.v

gases of combustion from vthe uid-iuel burner 25, to a desired degreeofsuperheat, such as, forv i example, a final temperature 4approximatingthe maximum temperature to be reached at any stage of our purifyingprocess bythe oil undergoing purification. The superheated steam passesfrom the heating coil 23 through the pipeline 28 t0 thesuperheated-steam header 21, whence all the various inert gasrequirements of ourprocess are supplied, with exception of water-freevinert gas used in de-aeration, as above described, or elsewhere, as willappear. From the header 21 superheated steam is supplied to the primaryatomizer- 22 through the pipeline 28.

From the primary atomizing device the atom'- ized mist of liquid oildroplets in inert gas flowsV through the coil 28 in the furnace 24, inpassing through which coil it is heated to a temperature lower than theinitial volatilization temperature, at the pressure condition existingin the coil 29, of the impurities to be distilled from the glyceridesbeing deodorized, but higher than the initial volatilization temperatureof the said impurities under the subsequent reduced absolute pressurecondition in the distilling column or tower.

Passing from the coil 29, the atomized mist travels through the pipeline30 and issues in the form of mist or spray from the nozzles 33 of thespray distributor 32 in the upper portion of the distilling column ortower I5. The flow of the atomized mist into the distilling column maybe regulated by the throttling valve 3|. The distilling column I5 isdivided into two4 separate chambers, I5s (upper) and I5i (lower) bymeans ofthesolid partition plate 35. The upper chamber`|5s is equippedwith spaced multiple bubble- 'cap trays 34 or equivalent devicesdesigned to promote contact between a falling liquid and a rising gas orvapor within the chamber.

superheated steam is admitted in controlled amount to the upper chamberI5s Aof the distilling column through the pipeline 36 and the controlvalve 31. This superheated steam, rising in the chamber I5s and bubblingthrough the liquid on the trays serves as vinert gas in -adding itsvapor pressure to that of the volatile impurities to be distilled fromthe glycerides being purined or deodorized, thus reducing thetemperature of vaporization of such volatiles. The superheated steamserves the additional function of replacing heat lost by radiation andthus helping maintain desired distillation temperatures in the chamberI5s.

The sprayed liquid mist descending through the tower forms a pool ofliquid on the uppermost bubble-cap tray 34, which pool of liquid is sub-.iected to intimate contact of the superheated steam rising through thebubble caps. The liquid overflows from tray to tray through theoppositely positioned alternate downflow pipes 38 and the volatileimpurities vaporize and pass upward with the superheated steam. In thismanner the bulk of the volatile impurities is distilled from the oilundergoing purification or deodorization.

In the deodorization of glyceride oils thevolatile impurities (odorousand flavoring materials) consist of aldehydes, ketones, fat acids andsimilar substances. In this general type of distillatory purication itisdesirable to prevent, insofar.

` separator is shown in Figure 5.

puritisor separated liquid entrainment to the l main body of liquid. \Inorder tofminimize return of such reilux condensation from the undersurface of the tower top,'we provide thev arresting ehimney-bame'amhefiat bane `au and the conical baille 4|. Any condensation from the innersury 1 face ofthe vupper dome of the distillingl chamber is collectedabovethe plate 39 and can be removed frorn the distilling zonecontinuously or intermittently by means ofthe valve 42ans the pipeline43 leading to the waste receiver 44.

More constructional detail of our entrainment The mixed vapors ofvolatile impurities and inert gas rising in the distilling chamber aredeflected by the flat baiiie 40 through the annular passage 45. Passingwith increased velocity through the throat 46 of the chimney-baille 39,the vapors lose velocity in the space 49 above said chimney-baffle andare again deflected through the second annular passage 41 around theconical baille 4|, passing from this space into the nozzle 48, thenceentirely away from the distilling column toward the vacuum-producingapparatus (not shown). Any

l unvaporized liquid entrained by the mixed vapors will tend to bedeposited during passage through the space' 49 above the chimney-baille39 because method comprises continuous1\y removing the oil undergoingtreatment from `alower portion of the distilling chamber" |5s, passingsaid oil through a heating zoneand returning it cantine` I uously to azone of lower absolute pressure than that existing in that portion ofthe distilling chamber |s from which the oil is withdrawn for e throughits overflow pipe, which is fitted with of velocity reduction afterpassage through the i and the pipeline 43 to the waste receiver 44 (Fig.

ure 1), which is maintained under vacuum by means of the connection 50to vacuum apparatus (not shown). v

The apparatus shown in Figure 5 is one example only of suitableequipment for separate the cup-seal 5|.

Overiiowing the cup-seal 5I, 'the oil undergoing purification ordeodorization forms a pool 1| in the lowest portion of the chamber |5s,just above the separating-plate 35.

From said pool 1|, the'glycerides, which by the time of reaching thisstage of the treating process have 'been lconsiderably deodorized orpuried, are continuously withdrawn through the valve 52 and the pipeline53 by means of the metering pump 54, which delivers the oil through thepipeline 55 to the secondary atomizer 56, in which the liquid isatomized with severaltimes its own volume of superheated steam accordingto the procedure described above in connection with the primaryatomization of the glycerides in the primary atomizer 22. Superheatedsteam is sup- 40 58 through the pipeline 59 and passes through removalof reflux condensation and separated i entrainment in our process. Thisfeature of our process invention resides in arrangement for separationand removal of such substances as a process step for contribution toimprovement of i the ilnal product in a process for continuousdistillatory deodorization or purification of glycerides.

y Referring again to Figure l, as the oil being purified descendsthrough the upper chamber |5s of the distilling column l5, itstemperature tends to fall, becauseof the absorption of heat in thevaporization of volatile impurities, also because of radiation lossesfrom the apparatus. We have found it desirable to restore thislost heat,in

order that the maximum distillatory effect may be applied to the oilunder treatment when it has reached a condition approaching purity. Itis at this stage of treatment that the concentration of impurities inthe oil is at its lowest, consequently the vapor pressure of theimpurities `at the liquid surface is low, causing maximum temperatureand minimum absolute pressure to be desirable at this stage forcompletion o f the purication or deodorization.

It has been found impractical to supply the additional heat necessary toregain maximum treating temperature by means of the superheated steaminjected into the chamber |5s because such the valve 66, the pipeline6|) and the valve (il` to the upper portion of the lower distillingchamber |5i of the distilling column I5. The chamber |51' is maintainedby means of suitable vacuum equipment (not shown) atthe lowest practicalabsolute pressure, in other words at the maximum practical vacuum. Thelower distilling chamber |5i is equipped with multiple bubble-cap trays62 and alternate oppositely positioned overflowl pipes 63, all of whichare similar to those installed in the upper distilling chamber |5s.Superheated steam is supplied from the header 21 through the pipeline 64and the control valve 65, enterr ing .the lower distillation chamber|51' below the lowermost bubble-cap tray thereof. The nozzle.

11 forms a vapor outlet for the" lower distilling chamber |51', saidvapor outlet being connected to suitable high-vacuum-producing apparatus(not shown).

The lower chamber |51' is provided withl suitable entrainment separationapparatus 18 and may be fitted, ii desired, with spray apparatus for theentering atomized mist of liquid in steam, similar to that shown inFigure 5.

It will be apparent that in our process the oil undergoing purificationor deodorization is withdrawn, vafter substantial treatment, from thelower portion of the upper distilling chamber |5s; is atomized withinert gas; is reheated to substantially maximum treating temperature; isdelivered to a zone of minimum absolute pressure at substantially saidmaximum treating temperature and in such zone of minimum pressure istreated with fresh inert gas (steam) which is relatively littlesaturated with vapors of volatile impurities.

It is to be noted that in such reheating .and transfer to a low-pressuredistilling zone of the glyceride oil being purified there is no mixing4of partially treated oil with entirely untreated oil, therefore nodilution of untreated oil with partially treated oil, which dilutionwould lower the partial vapor pressure (above the surface of theuntreated liquid) of the impurities to be distilled away, thus makingtheir separation from the oil more diiiicult.

As an alternative method of operation of the reheating feature of ourprocess we return the reheated atomized mist from the secondary coil 58to a median portion of the upper distilling chamber |5s, below one ormore of the bubble-cap trays of said chamber, instead of to the lowerchamber |5i. When operating in this manner the glyceride oil undergoingtreatment is withdrawn from the lower portion of the chamber I5s at suchrate that whenit is reheated as atomized mist and returned as suchreheated mist to a median portion of said chamber |5s`. the heat whichis so conveyed to said chamber will be suiiicient to overcomeevaporation and radiation losses therein and to cause the descendingstream of liquid to arrive atthe upper surface of the separating plate35 under a temperature condition which will be suitable for directtransfer of such liquid, without further reheating, to the zone of lowabsolute pressure in the chamber |51' for completion of the purifying ordeodorizingr process.

Under this method of operation of our process, (refer to Figure 1), thevalve 66 is closed, the valve, 61 remains open and the reheated atomizedmist from the coil 58 passes through the pipelines 59 and 68, enteringthe chamber |5s through the valve E9.

By returning the reheated atomized mist to the chamber |5s -ata pointbelow the point at which the original atomized mist of untreatedglycerides enters said chamber we avoid dilution of said untreatedglycerides by partially treated glycerides which dilution would resultin reduction of the partial vapor pressure of the impurities present inthe original untreated glycerides.

When returning the reheated atomized mist of oil in inert gas to amedian portion of the chamber |55', the surplus of partially purifiedoil (above the volume removed through the pipeline 53 for atomizationand reheating) accumulates in a pool 1| above the separating plate 35and because of admixture of reheated atomized mist entering the chamber|5s through the pipeline 68 and the valve 69, this pool of accumulatingoil is of elevated temperature, suitable for prompt ltransfer to thefinishing distilling chamber |5i..

In order suitably and automaticallly to effect such transfer we employthe regulating siphon loop shown in Figure 1 at 10 and in sectionaldetail in Figure 4.

Liquid overflowing from the\cupseal 5| falls to the separating plate 35,flowing out through the valve 52 'and the pipe 53 to the metering pump54. Surplus liquid not withdrawn by the pump 54 forms the pool 1| on theplate 35. Depth of the pool 1| is controlled by the height of the upperbranch s of the pipe loop 10. Rising in said upper branch to its maximumheight, the liquid overflows downward in the outer arm of the loop 10,rises in the inner arm of the lower branch 10i and enters the lowerdistilling chamber |5i above the bubble-cap tray 62.

Gravity siphoning of the pool of liquid 1| through the pipe loop 10 isprevented by the vent pipe 12, but since the absolute pressure in thechamber |5i above the plate 82 is lower than that in the chamber |53,`at a point just abovethe pool 1|, it is necessary to make suitableprovision to avoid discharge of vapor from the chamber Ils to thechamber |51' through the vent pipe 12 and the pipe loop 10.

It is for this purpose that we provide the lower branch 10i of the pipeloop 10, making such lower LVbranch of such dimensions that the distance13 will provide for sufficient static pressure of liquid in the innerarm of the lower branch 10i just to overbalance the pressuredifferential between the two chambers connected by the pipe loop 10. Itwill be apparent that the above-described design of overflow pipe loop10 and vent pipe 12 in combination will maintain the pool 1| at uniformdepth and will automatically transfer to the chamber |51' all surplus ofliquid entering said pool 1| over the amount withdrawn through thepipeline 53.

When all liquid flowing out through the pipeline 53 is returned from thesecondary mistheating coil to the upper distilling chamber, the amountof liquid overflowing through the pipe loop 10 will be equal to thetotal amount fed to the chamber |5s through the valve 3| (Figure 1). Thepipe loop 18 and the vent pipe 12 are equipped with shut-off valves 14,15 and 16 as shown in Figure 4.

In the lower distilling chamber |51' (Figure 1) the deodorization orpurification process is completed by vaporization of the small amount ofremaining impurities from the bubble-cap trays 62 .under minimumabsolutepressure and with the aid of the superheated steam which entersthrough the pipeline 64 and 'the valve 65.

Overowing from the cup-seal 19 beneath the lowermost tray, thecompletely deodorized oil accumulates ina pool 80 in the lower portionlof the chamber |5i, fromv which pool the oil is withdrawn continuouslythrough the valve 8| and the pipeline 82 by 'the metering pump 83. Thedepth of the pool 80 is regulated by the vented pipe loop 84 in thepipeline 82.

'Ihe metering pump 83 discharges the purified or deodorized oil throughthe pipeline 85 and the heat exchange apparatus 20, in Iwhich latter thetreated oil gives up a substantial amount of heat to the enteringde-aerated oil. Construction of the heat exchange apparatus 28 is suchthat there is no actual contact or mixing between the two types ofliquid flowing therethrough.

therein, from which it is removed continuously by the pump 93 whichpumps the treated oil through the filter 94 and the pipeline 95 to.point of storage or use (not shown).

. The bypass valve 96 at the pump 93 is controlled by the float 91within the receiver 8|, acting to maintain a substantially uniform levelof liquid in the pool' 92 together with. continuous flowthrough thefilter 94. The check-valve 98 acts to prevent entrance of air to thesystem through the discharge line to the filter.

The vacuum receiver 8| is connected through thenozzle 8|a tovacuum-producing apparatus (not-shown) or alternatively maybemaintained` with an internal atmosphere of any suitable water-freeinert gas, such as, for example, nitrogen or carbon dioxide gas. e

Suitablevacuum apparatus (not shown) is so arranged as to maintainlowest practicable absolute pressures at the two vapor outlet nozzlesand '11. If in any application of our invention it is desirable torecover the distilled impurities, suitable condensation apparatus forsuch recovery may be incorporated with the vacuum burner 25 areidentical with similarly numbered items in Figure 1. Construction of theupper distillation chamber |s is identical inail respects with thedesign shown in Figure 1, whereas the construction of the lowerdistillation chamber |5i is moded considerably as `will |be apparentfrom examination of Figure 2 When operating the process of our invention3 in apparatus assembled in accordance with Figure 2, the atomized mistof reheated oil dispersed in inert gas returning from the secondary mistheating coil 58 through the pipeline 80 and the valve 8| enters thelower distillation chamber |5i and passing downward through the trays 62thereof forms a pool 30 in the lower portion of said chamber.

superheated steam entering the lower portion of the chamber |5i throughthe pipeline 64' and solenoid-operated valve 65s passes through thesparger or perforated distributor 99 below the surface of the pool 80and bubbles through said 3 pool of liquid contributing to furtherpuriiication thereof before passing through the bubble-cap tray or traysB2 and thence out through the nozt zle l1 to the high' vacuum apparatus.The accumulation and discharge of the poo1'80 are controlled inconjunction with the iinal deodorization or purification of the oilbeing treated,

which nal deodorization or purification is per-l formed alternately insequence in the finishing vacuum vessels |0|la and |00b, which areconnected to high vacuum apparatus (not shown) through the nozzles |0|aand |0|b and are supplied with superheated steam from the header 21through the pipelines |92, |02a and |02b, the solenoid-operated valves|03sa and |03sb and the distribution spargers IMa and lnlb.

By means of the electrical time-cycle controller |05, thesolenoid-operated valves 65s, 8|s, |03sa so operated in sequence thatsmall charges of oil being treated are delivered in tum to each of thevessels |00a and |08b respectively, subjected therein to steaming bysuperheated steam at low .absolute pressure, each charge in turn and insequence in its respective vessel and for a definitely determined periodof time. Such treated charges l of oil are then withdrawn in sequencefrom said respective vacuum vessels |00a and |901: through thesolenoid-operated valves llllsa and llilsb and through the pipeline 82by the metering pump 83.

By operation in this manner insurance is had of absolute avoidance ofcontamination of iinished purified oil by even the .smallest possiblepercentage of oil only partially purified, while at the same time asubstantially constant flow of purified oil is maintained through themetering pump 83 and the pipeline 85, thus providing a constant ow ofheat from the finished purified oil to the untreated oil iiowing throughthe heat exchanger 20 (Figure 1).

It is to be noted that in this variant of our processinvention the pool80 is of variable rather than of iixed depth. A typical log of thetimecycle control of the iinal purification operation as practicedaccording to our process invention is set forth in Figure 6, forpurposes of example only, it being understood that the time-cycle may bevaried at will to suit the requirements of various oils which mayundergo purification or deodorization in accordance with the process ofour invention.

Referring to Figure 6, at initial or zero time, consider the pool 80 tobe substantially at a minimum, lor zero contents, the vessels |9|la and|00b to be empty, the valve 65s to be open, supplying superheated steamto the sparger 99, and all other solenoid-operated valves (3|s, |03sa,I03sb. |06sa, |98sb, Ill'lsa, |01sb) to be closed. Partially purifiedoil enters the pool 80 at such rate that at time of plus 25 minutes saidpool contains quantity Y of partially purified oil, which is a suitablequantity for a single charge for treatment in either of the finishingvessels |||8a or |0017. The electrical contacts of the time-cyclecontroller will then operate the solenoid valves as shown in Figure 6,at time plus 25, valve llllsb being manually held closed at thisbeginning point of the cycle only. The charge of partially puried oil isdelivered to vessel |80a, the delivery being represented by the graphiclines c-d between times plus 25 and plus 30. At time plus 30, theelectric controller closes valve 8Is and opens valves .85s and |03sa, asshown on the chart in Figure 6.

Admission of superheated steam through valve |83sa to the charge beingfinished in vessel' lllila continues until time plus 50, when valve|03sa is automatically closed by the time-cycle controller. 'I'he chargeof oil then rests under vacuum in the vessel Illlla until time plus 55,when valve Illlsa opens and the oil ows to pump 83, said iiow beingrepresented by the graphic line e-f. Simultaneously at the time plus 55,other solenoid-operated valves are automatically reset as shown inFigure 6 and a new charge of partially purified oil flows as representedby the lines c-d' from the pool to the vessel |891), there to receivefinishing treatment and be discharged in its turn, as represented by theline e-f', during the time interval between plus and plus 115. Theiinishing cycles then continue automatically and alternately between thevessels |0||a and Illlib. Examination of the graphic chart in Figure 6will make it clear that there will be continuous ow through the pump 83,said ow being represented by the repeating graphic lines e-f and ef-f.

In operation of our process by the method of time-cycle control abovedescribed, an alternative equipment assembly may be used, the chieffeature of which is combination of the distilling chambers |5s and |51of Figure 2 in a single chamber, in which case the pool 80 is located atthe bottomof said single chamber, the metering pump 54 withdraws oil forreheatlng from said pool 80 and the time-cycle apparatus controls anddirects the outflow from said pool 8 0 of excess oil above the quantityrecycled to a median portion of the single distilling chamber throughthe pipelines 59 and B8 and the valve 89.

Operation of our process in the equinlllentssembly indicated in Figure2, from the point oi' discharge of puriiied'oil from the pump 83 throughthe pipeline 85 toward the heat exchanger 20 and on through the coolingand ilnal filtration of the purified oil. is identical with itsoperation as described in connection with Figure 1.

Figure 3 of our drawings illustrates alternative equipment assembly tothat shown in Figure 1, differing from the latter only in thesubstitution of two entirely separate distilling chambers I5av and I5brespectively for the super-imposed chambers |53 and Iii of the tower I5of Figure 1. In operation of our process in the Figure 3 equipmentassembly according to the optional method of recycling incompletelypurified glycerides through the secondary atomizer 56, the secondarymist heating coil 58, pipelines 59 and 68 to the distillation chamberI5a, transfer of suitable amount of partially treated glycerides to thesecondary treating tower I5b can be accomplished by suitableproportioning of the flow of atomized mist between the valves 66 and 61,each of said valves being a metering throttle valve, thus passing thedesired amount of reheated glycerides in the form of atomized misttoeach of the primary and secondary distilling chambers at all times, or

by diverting to the secondaryy distilling chamber a suitable quantity ofunatomized partially purifled glycerides,v from the discharge pipeline55 of the metering pump 54, through the valve |08, the pipeline IUS andthe inlet valve H0. The valve I08a can be throttled to facilitate suchoperation.

From the descriptions as given hereinabove it will be readily apparentthat our process invention successfully meets the basic requirements ofa satisfactory continuous process for deodorization or purification ofglyceride oils, said requirements also having been set forth in fulldetail above.

By. use of the above-described operating methods, we, are able toproduce ina continuous process, deodorizedglyceride oils of improvedpurity and quality.

What we claim is:

1. In a process for continuous purification or deodorization ofglycerides the steps which com- -moving purified or deodorizedglycerides from said secondary distilling zone.

2. In a process for continuous purification or deodorization ofglycerides the steps which comprise subjecting said glycerides aftersuitable preheating to contact with a suitable inert gas incounter-current ilow in a primary distilling zone of sub-atmosphericpressure for a period of time sufficient to distill a substantial majorproportion of the odorous and other volatile impurities contained-insaid glycerides, continuously withdrawing partially puried or partiallydeodorized glycerides from a lower portion of said primary distillingzone, continuously reheating said withdrawn partially purified orpartially deodorized glycerides to suitable temperature for furtherdistillation of volatile impurities, transferring said reheatedglycerides to an independent secondary distilling zone ofsub-atmospheric pressure in which secondary zone said reheated partiallypurified or partially deodorized yglycerides are subjected to asecondary counter-current contact with substantially pure inert gas at acondition of sub-atmospheric pressure substantially lower than thepressure existing at the last point of contact of said partiallypurified or partially deodorized glycerides with inert gas in saidprimary distilling zone, maintaining said secondary counter-currentcontact of glycerides with inert gas in said secondary distilling zonefor a period of time suiilcient to distill the substantial remainingproportion of the odorous and other volatile impurities contained insaid glycerides and continuously removing puried or deodorizedglycerides from said secondary distilling zone.

3. In a process for continuous purification or deodorization ofglycerides the steps which comprise subjecting said glycerides aftersuitable preheating to contact with a suitable inert gas incounter-current ow in a primary distilling zone of sub-atmosphericpressure for a period of time suiilcient to distill a substantiallymajor proportion of the odorous and other volatile impurities containedin said glycerides, maintaining in a lower portion of said primarydistilling zone prise subjecting said glycerides after suitablepreheating to contact with a suitable inert gas in counter-current flowin a primary distilling zone of sub-atmospheric pressure for a period oftime sufllcient to distill va substantially major proportion of theodorous and other volatile impurities' contained in said glycerides,continuously v transferring partially purifled or partially vdeodorizedglycerides to an independent secondary distilling zone ofsub-atmospheric pressure 'in which secondary zone said partially puriedor partially deodorized glycerides are subjected to a a body of variabledepth of partially purified or partially deodorized glycerides,transferring measured volumes of said partially purified or partiallydeodorized glycerides alternately and sequentially to each' of multipleindependent secondary distilling zones of sub-atmospheric pressures eachsubstantially lower than the pressure existing at the last point ofcontact of glycerides and inert gas in said primary distilling zone,sequentially contacting said measured volcontact of glycerides withinert gas vin said umes of partially puried or partially deodorizedglycerides with substantially pure inert gas in each of said independentsecondary distilling zones for suitable time periods to completepuriilcation or deodorization of said measured volumes of glycerides andso regulating sequential discharge of said measured volumes ofglycerides from said multiple secondary distilling zones as to maintainsubstantially continues uniform outiiow therefrom of fully puried orfully deodorized glycerides free of any admixture of partially purifiedor partially deodorized glycerides.

4. 'I'he process nof continuous purification or deodorization ofglycerides which comprises pref "heating glycerides to a, temperaturesuitable for vacuum distillation of odorous or other volatileimpurities, expanding said preheated glycerides into a primarydistilling zone of sub-atmospheric pressure, subjecting said preheatedand expanded glycerides to contact with suitable inert gas incounter-current :dow in saidprimary distilling zone for sulcient time todistill a substantially major proportion of said odorous and othervolatile impurities, continuously removing said partially treatedglycerides to an independent secondarydistilling zone where saidglycerides are subjected in counter-current flow to contact withsubstantially pure inert gas substantially free of volatile impuritiesfor time sufficient to distill the remaining substantially minorproportion of said odorous and other'volatile impurities atsub-atmospheric pressure substantially lower than the pressure existingat the last point of contact between inert gas and partially treatedglycerides in said primary distilling zone and removing puriiled ordeodorized glycerides substantially free of 'any untreated or partiallyuntreated glycerides continuously from said secondary distilling zone.

5. The process of continuous purification or deodorization of glycerideswhich comprises preheating glycerides to a temperature suitable forvacuum distillation of odorous or other volatile impurities, expandingsaid preheated glycerides into a primarydistilling zone ofsub-atmospheric pressure, subjecting said preheated and expandedglycerides to contact with suitable inert gas in counter-current now insaid primary vdistilling zone for sufficient time to distill asubstantially major proportion of said odorous and. other volatileimpurities, continuously removing saidv par-y tially treated glyceridesfrom 'said primary distilling zone, continuously reheating said removedi.

partially treated glycerides to a temperature'suitable' for furthervacuum distillation of odorous and other volatile impurities,continuously transferring said reheated partially treated glycerides toan independent secondary distilling zone where said reheated glyceridesare subjected in countertacting'the mixture of partially treatedglycerides current iiow to contact with substantially pure inert gassubstantially free of volatile impurities for time sumcientrto distillthe remaining substantially minor proportion of saidodorous and othervolatile impurities at sub-atmospheric pressure substantially lower thanthe pressure existing at the last point of contact between inert gas andpartially treated glycerides in said primary distilling zone andremoving puried or deodorized glycerides substantially free of anyuntreated or partially treated glycerides continuously from saidsecondary distilling zone. y

6. The process of continuous purication or deodorization of glyceridesas described in claim V4 which is characterized by continuouslywithdrawing partially purified or partially deodorized'glycerides from alower portion of the primary distilling zone, continuously reheatingsaid withdrawn partially treatedglycerides to a temperature suitable forfurther distillation of odorous zone Where said returned reheatedglycerides are. mixed with other partially purified or partiallydeodorized glycerides free of any wholly unpuriso producedv with inertgas in counter-current ow within said primary distilling zone. v

i 8; The process of continuous deodorization which comprises preheatingglycerides to a temperature suitable for vacuumv distillation of odorousor other volatile impurities, expanding said preheated glycerides into aprimary distilling zone of sub-atmospheric pressure, subjecting saidpreheated and expanded glycerides to contact with suitable inert gas incounter-current flow in said primary distilling zone for a period oftime sufficient to distill a substantially major proportionvof theodorous and other volatile impurities 'contained in said glycerides,maintaining in a lower portion of said primary distilling zone a body ofvariable depth ofpartially purified or partially deodorized glycerides,transferring measured volumes of said partially puried or partiallydeodorized glycerides alternately and sequentially to each of multipleindependent secondary distilling zones of sub-atmospheric pressures eachsubstantially lower than the pressure existing at the last point ofcontact of glycerides and inert gas in said primary distilling zone,sequentially contacting said measured volumes of partially purified orpartially deodorized glycerides with substantially pure inert gas ineach of lsaid independent secondary distilling zones for suitable timeperiods to complete purification or deodorization of said measuredvolumes of glycerides and so regulating sequential discharge of saidmeasured volumes of glycerides from said multiple secondary distillingzones as to maintain substantially continuous outow therefrom of fullypurified or fully deodorized glycerides free of any admixture ofpartially untreated or Wholly untreated glycerides.

9. The process of continuous puriiication or deodorization of glyceridesas described in claim 8 which is characterized by continuouslywithdrawing partially puried or partially deodorized glycerides from alower portion of the primary distilling zone, continuously reheatingsaidwithdrawn partially treated glycerides to a temperature suitable forfurther distillation of odorous .and other voltatile impurities,continuously returning said reheated partially treated glycerides to amedian portion of said primary distilling zone where said returnedreheated glycerides are mixed with other partially purified or partiallydeodorized glycerides free of any wholly unpurifiedor whollyundeodorized glycerides and contacting the mixture of partially treatedglycerides so A, produced with inert gas in counter-currentv ilow withinsaid primary distilling zone.

ed or wholly undeodorized glycerides and contacting the mixture ofpartially treated glycerides so produced with inert gas incounter-current flow within said primary distilling zone.

7. The process of continuous puriiication or 'deodorization ofglycerides as described in claim 5 which is characterized bycontinuously withdrawing partially puried or partiallydeodorized glyc-10. The 'process of continuous puriiication or deodorization ofglycerides as describedin claim distilling zone, continuously reheatingsaid withdrawn partially treated glycerides to a temperature'suitableforfurther distillation of odorous and other volatile impurities,continuously returning said reheated partially treated glycerides to amedian portion of said primary distilling zone 'vhere said returnedreheated glycerides are mixed with other partially puried or partiallydecdoriaed ,'rlycerides free of any wholly unpurilied or vflinllyundeodorized glycerides and contacting the mixture of partially treatedglycerides so produced with inert gas in counter-current dou' Withinsaid primary distilling zone While se carating entrained liquids andreuxed or re'- iluxing condensed vdlatiles from the vapors present inthe distilling zone o1' zones at a point or points within said zone orzones above the upper most liquid body therein, collecting saidseparated entrained liquids and condensed volatiles within saiddistilling zone or zones, Wholly removing said separated entrainedliquids and condensed volatiles from said distilling zone or zonesWithout any readmixture with the glycerides undergoing puriiiication ordeodorization of any portion of said separated entrained liquids orcondensed volatiles.

1l. The process oi continuous purification or deodorization ofglycerides which comprises preheating glycerides to a temperaturesuitable for vacuum distillation of odorous or other volatileimpurities, expanding .said preheated glycerides into a primarydistilling zone of sub-atmospheric pressure. subjecting said preheatedand expanded glycerides to contact with suitable inert gas incounter-current flow in said primary distilling zone for sufficient timeto distill a substantially major proportion of said odorous and othervolatile impurities, continuously removing said partially treatedglycerides from said primary distilling zone, continuously reheatingsaid removed partially treated glycerides to a temperature suitable forfurther vacuum distillation of odorous and other volatile impurities,continuously transferring said reheated partially treated glycerides toan independent secondary distilling zone where said reheated glyceridesare subjected in countercurrent flow to contact with substantially pureinert gas substantially free of volatile impurities for time sufficientto distill the remaining Asubstantially minor proportion of said odorousand other volatile impurities at sub-atmospheric pressure substantiallylower than the pressure existing at the last point of contact betweeninert gas and partially treated glycerides in said primary distillingzone and removing purified or deodorized glycerides substantially freeof any untreated or partially treated glycerides continuously from saidsecondary distilling zone, While continuously withdrawing partiallypurified or partially deodorized glycerides from a lower portion of theprimaryy distilllng zone, continuously reheating said withdrawnpartially treated glycerldes to a temperature suitable for furtherdistillation 'of odorous and other volatileimpurities, continuouslyreturningI said reheated partially treated glycerides to a medianportion of said primary distilling zone where said returned reheatedglycerides are mixed with other partially purified or partiallydeodorized glycerides free of any wholly unpuried or wholly undeodorizedglycerides and contacting the mixture of partially treated glycerides soproduced with inert gas in counter-current flow Within'said primarydistilling zone, in which process separation of entrained liquids andreuxed or reuxing condensed volatiles from the vapors present in thedi-stilling zone or zones is accomplished within said distilling zone orzones at a point or points above the uppermost liquid body therein, saidseparated entrained liquids and condensed volatiles being collectedWithin and wholly -removed from said distilling zone or zoneswithoutreadmixture with the glycerides undergoing purication ordeodorization of any portion of said separated entrained liquids orcondensed volatiles.

12. The process of continuous purication or deodorization of glyceridesas described inA claim 4 which is characterized by continuouslyWithdrawing partially purified or partially deodorized glycerides from alower portion of the primary distilling zone, continuously reheatingsaid withdrawn partially treated glycerides to a temperature suitablefor further distillation of odorous and other volatile impurities,continuously returning said reheated partially treated glycerides to almedian portion of said primary distilling zone Where said returnedreheated glycerides are mixed with other partially purified or partiallydeodorized glycerides free of any wholly unpuried or wholly undeodorizedgiycerides and con- .tacting the mixture of partially treated glyceridesso produced with inert gas in counter-current flow Within said primarydistilling zone while separation of entrained liquids and reiiuxed orundergoing purication or deodorization of any portion of said separatedentrained liquids or condensed volatiles.

ALAN PORTER LEE. WALTER GRAY KING, JR.

CERTIFICATE 0F CORRECTION. patent No. 2,568,669. February 6, 19145.

ALAN PORTER LEE, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 55, for "Practially" rea-d -Practica11y; and lines66-67, for "miximum" read --maximum--g page 1|., first column, line 56,for "(Fig." read (Figpage?, second column, line 65, claim 5, for"centimes" read --continuousug page 8, second column, line 58, claim 9,for "voltatile read -vo1ati1e; and that the said Letters Patent shouldbe read with this correction therein that the same may confom to therecord of the case in the Patent Office. l

signed and sealed this 5th day of June, A. D. 19145.

Leslie Frazer (Seal) Acting Commissioner of Patents.

